Graphical tablets, including "touchscreen" tablets and pen-based tablets (hereinafter pen tablets) are becoming more commonplace for the entry of graphical information into a computer. Pen tablets are also being used to a greater degree as an input device for game apparatus and home intelligent devices. In such applications, the tether used to attach the pen tablet to the intelligent device is cumbersome and tends to restrict the use of such pen devices. On the other hand, existing wireless pen tablets use an unacceptable amount of battery power since the amount of data transmitted from the pen tablet is large.